Recoil brake

Abstract

A recoil brake 10 for a gun includes a cylinder 11 and a piston 12 which is slidably mounted in cylinder 11, with braking force being supplied when piston 12 is extracted by the recoil movement of the gun barrel and presses hydraulic fluid through a narrow flow cross section. In order to be able to accommodate the recoil brake in an area protected against enemy fire or shrapnel, even if space is cramped, the structural length of the recoil brake is reduced by including a further piston rod in the form of a hollow cylinder which is disposed within cylinder 11 so as to coaxially surround the first piston rod 12. This second piston rod 13 is extracted only after the first piston rod 12 has reached its maximum extended position.

What I claim is: 
     
       1. A recoil brake for a gun having a barrel, comprising: an outer cylinder to contain hydraulic fluid;   a hollow first piston rod mounted in said outer cylinder for sliding movement between an inserted position and an extended position, said first piston rod being operatively connected to said gun barrel and being pulled out of said outer cylinder by recoil movement of said gun barrel   a hollow second piston rod slidably mounted in said outer cylinder and cooperating with said first piston rod, said second piston rod coaxially surrounding said first piston rod and being extended by said first piston rod after said first piston rod has been pulled out of said outer cylinder to an intermediate position that lies between said inserted and extended positions, said second piston rod being spaced apart from said outer cylinder to provide a pressure chamber between said outer cylinder and said second piston rod;   an intermediate hollow member disposed between said first and second piston rods, said intermediate hollow member being attached to said second piston rod and being spaced apart from said second piston rod, said intermediate hollow member additionally being spaced apart from said first piston rod to provide another pressure chamber between said first piston rod and said intermediate hollow member;   a first piston connected to said first piston rod to displace hydraulic fluid when said first piston rod is pulled out of said outer cylinder, said first piston surrounding said first piston rod, said first piston having an aperture therein and having a flow channel communicating with said another pressure chamber;   equalization means for equalizing hydraulic pressure between said pressure chamber and said another pressure chamber, said equalization means including at least one bore in said intermediate hollow member and at least one bore in said second piston rod;   first choke means, cooperating with said first piston and defining a narrow flow cross section, for imparting a braking force on said gun barrel when hydraulic fluid is displaced as said first piston rod is pulled out of said outer cylinder, said first choke means including a control rod which is operatively connected to said second piston rod, said control rod extending through said aperture in said first piston and being exposed to said another pressure chamber via said flow channel in said first piston, said control rod having a cross sectional area which changes along the length thereof to control said narrow flow cross section of said first choke means;   a second piston connected to said second piston rod to displace hydraulic fluid when said second piston rod is extended, said second piston being exposed to said pressure chamber and having a piston area that is greater than the piston area of said first piston; and   second choke means, cooperating with said second piston and defining a narrow flow cross section, for imparting a braking force on said gun barrel when said hydraulic fluid is displaced as said second piston rod is extended, said second choke means including a control sleeve which is provided on said outer cylinder and which has a surface configured to control said narrow flow cross section of said second choke means.   
     
     
       2. The recoil brake of claim 1, wherein a restoring means cooperates with the recoil brake to push said first piston rod back to its inserted position after the recoil has been braked, wherein said second piston rod has a start position, and further comprising dogs that are positioned for abutment by said first piston rod to return said second piston rod to said start position when said first piston rod is pushed back to said inserted position. 
     
     
       3. The recoil brake of claim 1, wherein said first piston rod, said second piston rod, and said intermediate hollow member are cylindrical. 
     
     
       4. The recoil brake of claim 1, wherein said control sleeve of said second choke means has first and second ends and has an internal surface which is exposed to said pressure chamber, said internal surface having an elongated groove which extends from a position adjacent said first end of said control sleeve to a position adjacent said second end of said control sleeve.